Electric vehicle and on-board battery charging apparatus therefor

ABSTRACT

An electric vehicle and a range extender engine are shown including the controls to operate the same.

This application is a continuation of PCT Application Ser. No.PCT/US2010/049167.

FIELD OF THE INVENTION

The subject disclosure relates to electric vehicles and a chargingsystem therefore, and in particular, an onboard engine generator forcharging the battery packs. The vehicle has extended operating rangewith coupled combustion engine, whereby it concerns a serial hybridelectric vehicle according to the. EC-Directives.

BACKGROUND OF THE INVENTION

Electric vehicles are known having battery packs which drive an electricmotor which in turn drives the vehicle wheels. Two types of vehicles areknown using electric motors, the first is a hybrid electric vehiclewhere the vehicle includes an electric motor and an onboard fuel drivenengine, where the engine is used to drive the wheels under certainvehicle circumstances.

Another type of electric vehicle also has an onboard fuel driven engine,but the engine is only used to drive a generator, which in turn chargesthe batteries. The latter type arrangement is referred to as rangeextender as the onboard engine/generator extends the range that thevehicle can travel on the battery pack before a complete recharge.

With this type of hybrid vehicle, also called electric vehicle withRange Extender, a combustion engine is coupled to an electric machineacting as a generator. The combustion engine delivers its power to thegenerator, which transforms the rotary motion into electric energy andsupplies it to the battery to extend the range (travelling distance of avehicle without external charge). Alternatively, the electrical energycould be connected to an electric traction motor of the vehicle. In thismanner the combustion engine can be operated with a very good efficiencyin all operating aspects, which has a positive effect on CO₂ emissionsand fuel consumption of the aggregate. Multiple aspects of a rangeextender design and operation in a vehicle are addressed in thisapplication.

A first factor of such aggregates is the coupling of the combustionengine to the generator, because the high combustion power of the enginecauses substantial rotary imbalances and deformation on the crank shaft.In general, in order to couple a generator to a combustion engine,several solutions are known today, whereby the design of the generatorplays an important role. The known solutions, e.g. according to DE 19735 021 A1 or DE 10 2007 024 126 A1, concern applications in so-calledparallel hybrid vehicles which have a complex coupling system in whichthe coupling parts are coupled axially.

Various solutions for the connection of the generator shaft with thecrank shaft may be envisaged, for example an elastomer coupling could beprovided, which however requires very much space axially as well asradially, and large tolerances must be chosen. These couplings alsocannot absorb the required increasing dynamic torque.

Other connections include connection of the shafts through a cone ortapered coupling. The connections provide a rigid connection, but needspace in length and diameter in order to have enough rigidity.Furthermore, axial tolerances are problematic because during theassembly, the mounting position dependent on the tightening torquecannot be exactly determined. Assembly and removal are also made moredifficult.

Other connections include connection of the shafts through internalteeth. These connections however are complex to manufacture; thegenerated momentum provoke a mechanical play and running noise if athrust tolerance is used; assembly and removal are problematic withcrimp connections; and assembly length/space requirements are relativelyhigh.

Based on this state of the art, it is an object of the invention toprovide a serial hybrid electric vehicle in which the connection betweenthe combustion engine and the generator is very precisely adjusted andhas a torsion-resistant design, yet enabling both weight savings andeasy assembly.

Another object is to enable an efficient length adjustment of thegenerator shaft and the crank shaft in case of variations intemperature.

Another object is to enable the generator to serve as the flywheel massof the engine, reducing both the cost and the weight.

Another object is to provide minimum weight to the engine by eliminatingsuch peripheral components as a tradition oil pump. Rather, a method ofproviding a “pump” from suction created during the compression stroke isshown herein.

Another object is to provide components within the engine requiringminimal lubrication.

Another object is to provide an engine design having a “run-ready”condition.

Another object is to provide an optimized heating/cooling system for therange extender and vehicle.

With the present design in accordance with the drawings, the generatoris suitable for the mounting to different engines, whereby the couplingcan in principle be made by any chosen connection of the shafts and thehousing. Engine and generator are independent and are connected by aconnecting member. For a single-cylinder engine with a very short crankshaft, this design is the most sensible solution because of the separatebearing of the generator rotor allows the air gap in the generator to bekept small in order to achieve a high efficiency. The bending moment inthe crank shaft during combustion, as well as the bearing clearances onthe short distance between the bearings can in an appropriatearrangement be carried by the generator bearing, thus preventing contactof the rotor and the housing.

Depending on the design and the stability of the shaft connectionbetween the combustion engine and the generator, the generator may serveas a flywheel mass for the combustion engine, which is however notwithout difficulty because of the generated momentum, but is solved,with the solution at hand.

The present disclosure relates to an engine/generator and the controlmechanism for a range extender engine.

In one embodiment, a serial hybrid electric vehicle is coupled with acombustion engine which serves to extend the operating range. Thecombustion engine is coupled to the generator of the range extender by aself-centering spur gearing.

In another embodiment of the invention, a serial hybrid electric vehicleis coupled with combustion engine which serves to extend the operatingrange. A crankshaft of the engine is fixedly connected to a shaft of thegenerator. A fixed bearing and a first floating bearing are located onthe side of the generator and the bearings on the side of the engine areconfigured as floating bearings in order to absorb the length extensionsof the shafts caused by temperature influence.

In another embodiment of the invention, a combustion engine, comprises acrankcase defining a journal area and an oil sump; a cylindercommunicating with the crankcase; a cam chain chamber discrete from thecrankcase; a crankshaft journalled in the journal area of the crankcase,with a first end extending into the cam chain chamber and a second endextending through the crankcase; a piston positioned in the cylinder; aconnecting rod coupling the piston to the crankshaft; a head above thecylinder having at least one cam therein operating valves in the head; afirst gear positioned on the crankshaft first end and positioned in thecam chain chamber; a second gear positioned on an end of the cam; achain entrained around the first and second gear; a passageway definedbetween the oil sump and the crankshaft; wherein, when the piston ismoving from a bottom dead center position to a top dead center position,a vacuum is created, siphoning oil through the passageway to lubricateat least a portion of the crankshaft.

In another embodiment of the invention, a combustion engine, comprises acrankcase defining a journal area and an oil sump; a cylindercommunicating with the crankcase; a cam chain chamber discrete from thecrankcase; a crankshaft journalled in the journal area of the crankcase,with a first end extending into the cam chain chamber and a second endextending through the crankcase; a piston positioned in the cylinder; aconnecting rod coupling the piston to the crankshaft; a head above thecylinder having at least one cam therein operating valves in the head; afirst gear positioned on the crankshaft first end and positioned in thecam chain chamber; a second gear positioned on an end of the cam; achain entrained around the first and second gear; a port communicatingbetween the crankcase and the cam chain chamber; and a valve allowingthe flow of blow by gases and compressed gases into the cam chainchamber when the piston is moving from a top dead center position to abottom dead center position.

In another embodiment of the invention, a combustion engine comprises avehicle, comprising: an electric propulsion drive assembly; a firstcooling circuit for the electric propulsion drive assembly; an engine,including a crankcase having an oil sump; and a pre-heater for the oilsump in fluid communication with the first cooling circuit forpre-heating engine oil.

In another embodiment of the invention, a combustion engine comprises acrankcase having an oil sump; and a pre-heater for pre-heating engineoil in the oil sump, the pre-heater being integrated with the oil sumpof the crankcase.

In another embodiment of the invention, a combustion engine comprises acrankcase defining a journal area and an oil sump; a cylindercommunicating with the crankcase; a cam chain chamber discrete from thecrankcase; a crankshaft journalled in the journal area of the crankcase,with a first end extending into the cam chain chamber and a second endextending through the crankcase; a piston positioned in the cylinder; ahead above the cylinder having at least one camshaft therein operatingvalves in the head; a first gear positioned on the crankshaft first endand positioned in the cam chain chamber; a second gear positioned on anend of the cam; a chain entrained around the first and second gear; andan oil distribution mechanism for distributing oil in the oil sump ontothe cam chain for delivering lubrication oil to the head.

In another embodiment of the invention, a combustion engine comprises acrankcase defining a journal area and an oil sump; a cylindercommunicating with the crankcase; a cam chain chamber discrete from thecrankcase; a crankshaft journalled in the journal area of the crankcase,with a first end extending into the cam chain chamber and a second endextending through the crankcase; a piston positioned in the cylinder; ahead above the cylinder having at least one camshaft therein operatingvalves in the head; a first gear positioned on the crankshaft first endand positioned in the cam chain chamber; a second gear positioned on anend of the cam; a chain entrained around the first and second gear; andan oil distribution member within the head to deliver oil to the camlobes.

In another embodiment of the invention, a control system is provided foran electric vehicle, where the electric vehicle includes a drive axlecoupled to a chassis. The control system comprises an engine generatorincluding an electrical machine driven by an engine, the enginegenerator being configured to generate electrical power; a controllerconfigured to electronically control the engine of the engine generator;an electric motor configured to drive the drive axle of the electricvehicle; a battery configured to drive the electric motor and to receivethe electrical power generated by the engine generator; and a modeselection device in communication with the controller for selecting oneof a plurality of operating modes of the engine generator, the pluralityof operating modes providing variable rates of electrical powergeneration.

An inventive method of controlling an engine of an electric vehicleincluding a generator driven by the engine and an electric motor drivenby an onboard battery, the method includes the steps of: monitoring avehicle speed of the electric vehicle; starting the engine of theelectric vehicle when the vehicle speed increases to a firstpredetermined threshold; generating electrical power with the generatorfor use by the electric vehicle; and stopping the engine of the electricvehicle when the vehicle speed decreases to a second predeterminedthreshold.

An inventive method of controlling an engine of an electric vehicleincluding a generator driven by the engine and an electric motor drivenby an onboard battery, the method includes the steps of: providing avehicle control unit for controlling an electrical system of theelectric vehicle, the electrical system including the electric motor andthe battery; driving the electric motor with the battery; monitoring aplurality of parameters of the battery with the vehicle control unit,the plurality of parameters including at least one of a voltage level, acharge level, and a temperature level; starting the engine of theelectric vehicle when each of the plurality of parameters of the batteryare below a predetermined minimum threshold; generating electrical powerwith the generator for use by the electric vehicle; and charging thebattery of the electric vehicle with the generated electrical power.

An inventive method of charging a battery of an electric vehicle, theelectric vehicle including a generator driven by an engine and anelectric motor driven by the battery, the electric motor beingconfigured to drive a drive axle of the electric vehicle to move theelectric vehicle. The method includes the steps of providing aregenerative braking system with the electric vehicle, the regenerativebraking system being configured to transfer kinetic energy of theelectric vehicle to the electric motor to rotate the electric motor in areverse direction; rotating the electric motor in a forward directionwith electrical power from the battery to move the electric vehicle;generating a first electrical current with the generator, the firstelectrical current being routed to the battery; rotating the electricmotor in a reverse direction with the regenerative braking system toslow movement of the electric vehicle and to generate a secondelectrical current, the second electrical current being routed to thebattery; charging the battery with the first and second electricalcurrents; monitoring the first and second electrical currents during thecharging step to determine a total electrical current supplied to thebattery; and removing the first electrical current from the battery uponthe total electrical current exceeding a first predetermined threshold.

In another embodiment, an electric vehicle, comprises a chassis; a driveaxle coupled to the chassis; an electric motor configured to drive thedrive axle; a battery configured to drive the electric motor; an enginegenerator configured to generate electrical power and to provideelectrical power generated to the battery; and a mass supported by theengine to dampen vibrations of the engine.

Finally, a method of controlling an engine of an electric vehicle, wherethe electric vehicle includes a generator driven by the engine, anelectric motor driven by a battery, and a transmission having aplurality of gears, the method including the steps of: monitoring avehicle speed of the electric vehicle; placing the transmission of theelectric vehicle in a neutral gear; receiving a user input configured toactivate the engine of the electric vehicle; starting the engine of theelectric vehicle upon receipt of the user input and upon the vehiclespeed of the electric vehicle being at or below a predeterminedthreshold value; generating electrical energy with the generator;routing the electrical energy to the battery; and charging the batteryof the electric vehicle with the generated electrical energy.

The invention will now be explained in more detail in the following bymeans of drawings of an exemplary embodiment, where:

FIG. 1 illustrates a representative view of an exemplary electricalsystem of an electric vehicle according to one embodiment;

FIG. 2 illustrates exemplary control logic for controlling the rangeextender of the electrical system of FIG. 1;

FIG. 3 is a graph illustrating vehicle speed versus engine speed andthrottle opening percentage in an exemplary battery hold mode of therange extender of FIG. 1;

FIG. 4 is a graph illustrating exemplary vehicle drive power consumptionand an exemplary battery hold mode of the range extender of FIG. 1;

FIG. 5 is a graph illustrating an exemplary range extended mode and anexemplary battery charge mode of the range extender of FIG. 1;

FIG. 6 is schematic view of the vehicle system cooling system;

FIG. 7 shows a perspective view of the engine of the present embodiment;

FIG. 8 shows a perspective view of the opposite side of the engine shownin FIG. 7;

FIG. 9 shows a side view of the engine shown in FIG. 7;

FIG. 10 is a cross-sectional view through staggered lines 10-10 of FIG.7;

FIG. 11A is a perspective view of the oil sump;

FIG. 11B is an underside perspective view of the oil sump, partiallyexploded;

FIG. 12 is a cross-sectional view through lines 12-12 of FIG. 11A;

FIG. 13 is a cross-sectional view through lines 13-13 of FIG. 11A;

FIG. 14 is an upper partially exploded view of the crank housing fromthe generator mount side;

FIG. 15 is a lower partially exploded view of the crank housing from thegenerator mount side;

FIG. 16 is an upper partially exploded view of the crank housing fromthe cam chain drive side;

FIG. 17 is a lower partially exploded view of the crank housing from thecam chain drive side;

FIG. 18 shows a cut away perspective view of the crank assembly;

FIG. 19 shows an upper perspective view of the crank assembly;

FIG. 20 shows an upper perspective view of the head assembly and valvecover;

FIG. 21 is a perspective view of the head casting portion;

FIG. 22 is a cross-sectional view through line 22-22 of FIG. 9;

FIG. 23 shows the inner cam chain cavity with the cover removed;

FIG. 24 shows a cross-sectional view through lines 24-24 of FIG. 22;

FIG. 25 shows an underside perspective view of the valve cover;

FIGS. 26 and 27 show perspective views of the oil distribution mechanismlocated within the valve cover;

FIG. 28 shows a perspective of a potential mounting orientation andstructure for the range extender within a vehicle;

FIG. 29 shows an enlarged view through the cam shaft drive chambershowing the oil scraper positioned between the links of the cam chain;

FIG. 30 shows a perspective view of the assembled valve cover with aportion of the outer cover member broken away to show the internal oildistribution mechanism;

FIG. 31 is a perspective view similar to that of FIG. 30 showing theentire internal oil distribution mechanism within the valve cover;

FIG. 32 shows a cross-sectional view of the engine and generator of FIG.28;

FIG. 33 shows an enlarged sectional view of the portion denoted in FIG.32;

FIG. 33 shows the crank shaft of the combustion engine in a perspectiverepresentation;

FIG. 35A and 35B show the bearings on the shafts;

FIG. 36 shows a diagrammatical sketch of an engine dampening system foruse with the above mentioned engine;

FIG. 37 shows a diagrammatical sketch of an alternate engine dampeningsystem of the version shown in FIG. 36; and

FIG. 38 shows a diagrammatical sketch of an alternate engine dampeningsystem of the version shown in FIG. 36.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The embodiments disclosed herein are not intended to be exhaustive orlimit the disclosure to the precise forms disclosed in the followingdetailed description. Rather, the embodiments are chosen and describedso that others skilled in the art may utilize their teachings.

Referring initially to FIG. 1, an electrical system 10 is shown forcontrolling the operation of an electric vehicle. The electric vehiclemay be a car, an all-terrain vehicle, a sport utility vehicle, awatercraft, or any other suitable vehicle. In the illustratedembodiment, electrical system 10 is configured for use with a car.Electrical system 10 includes a vehicle battery 36 that provideselectrical power to a vehicle motor 48 for driving a drive axle 50 ofthe electric vehicle. A range extender 16 serves to generate electricalpower for utilization in electrical system 10, such as for chargingvehicle battery 36 or for powering vehicle motor 48 of the electricvehicle. Electrical system 10 includes a vehicle control unit (VCU) 12in communication with an electronic control unit (ECU) 14. In theillustrated embodiment, ECU 14 is an electronic controller configured tocontrol the operation of an engine of range extender 16. ECU 14illustratively provides control signals to the engine of range extender16 via a drive-by-wire system 18. ECU 14 may control, for example, thethrottle position, the engine speed, the ignition timing, and otherparameters of the engine of range extender 16. Range extender 16includes an electrical generator 17 coupled to and driven by the engine.See, for example, range extender 16 having generator 17 and an engine asillustrated in FIGS. 7-31 and described herein.

VCU 12 is an electronic controller configured to control the electricalsystems and subsystems of the electric vehicle. For example, VCU 12 maycontrol fan and water pump motors, control and monitor vehicle speed andvehicle motor speed, receive and execute driver inputs and commands, andcontrol the heating and cooling system of the electric vehicle. In oneembodiment, VCU 12 includes a microprocessor having software thatcontains instructions for controlling the startup and operation mode ofrange extender 16. In the illustrated embodiment, VCU 12 is configuredto apply switched voltage to ECU 14 according to the control logicillustrated in FIG. 2 to start range extender 16. In one embodiment, ECU14 controls the engine of range extender 16 using vehicle parametersprovided by VCU 12. Alternatively, ECU 14 may include a microprocessorhaving software for executing the control logic of FIG. 2 and forcontrolling range extender 16.

A communication network 40 is provided for communication between VCU 12and various components and devices of electrical system 10.Communication network 40 illustratively uses controller area network(CAN-bus) protocol, although other suitable communication protocolsbetween components of electrical system 10 may be used. In theillustrated embodiment, VCU 12 communicates with ECU 14, a comfortsystem 20, a driver interface 22, a vehicle battery 36, a rectifier 42,an inverter 44, a charger 52, and a converter 54 over a communicationnetwork 40.

Comfort system 20 illustratively includes a heating system 76 and an airconditioning system 78. In the illustrated embodiment, VCU 12 controlsthe operation of heating system 76 and air conditioning system 78.Driver interface 22 may include user inputs that allow a user to adjustthe settings of the comfort system 20 of the electric vehicle.

Electrical system 10 further includes driver inputs 24 and a gearselector 26. Driver inputs 24 illustratively include a brake input 72, athrottle input 73, and a mode selector 74. Brake input 72 provides asignal to VCU 12 that causes VCU 12 to slow or stop movement of theelectric vehicle by applying brakes to the wheels, for example, of theelectric vehicle. In the illustrated embodiment, the electric vehicleincludes a regenerative braking system that works in tandem with amechanical brake. In particular, the mechanical brake is configured toassist with braking when the regenerative brake is unable to applyadequate braking force to meet the brake input demand. Throttle input 73provides a signal to VCU 12 representative of the position of a throttleinput device, such as a pedal, lever, or twist-grip device. In response,VCU 12 controls the speed and torque of vehicle motor 48 based on thesignal provided with throttle input 73.

Mode selector 74 provides a signal to VCU 12 representative of aselected operating mode of the electric vehicle. Exemplary operatingmodes include an economic mode and a sport mode. In an economic mode,the driving performance of the vehicle is limited such that the life andperformance of battery 36 is maximized. For example, rapid accelerationof the vehicle may be limited in an economic mode. A sport mode providesmaximum wheel performance (e.g. rapid acceleration and power) whileexpending the energy of vehicle battery 36 at a potentially faster ratethan in the economic mode.

Gear selector 26 provides a signal to VCU 12 representative of aselected gear of operation of the electric vehicle. In the illustratedembodiment, gear selector 26 includes a forward gear, a reverse gear,and neutral. Gear selector 26 and mode selector 74 may be in the form ofa switch, a button, a lever, or other suitable device configured toreceive a user input for selecting the mode or gear of operation of thevehicle.

Driver interface 22 includes a mode select input 82 that provides asignal to VCU 12 representative of a selected operating mode of rangeextender 16. Mode select input 82 is also configured to start and stoprange extender 16. Exemplary operating modes of range extender 16include a battery hold mode, a range extended mode, and a battery chargemode, as illustrated in FIGS. 4-5 and described herein. In a batteryhold mode, range extender 16 operates to maintain the charge of vehiclebattery 36 at a substantially constant level. In particular, rangeextender 16 generates approximately the same or more electrical energythan the electric vehicle on average consumes during operation of thevehicle. In a battery charge mode, range extender 16 operates toincrease the charge of vehicle battery 36. In particular, range extender16 generates substantially more electrical energy than is drawn fromvehicle battery 36 on average during operation of the vehicle. In arange extended mode, range extender 16 operates to extend the range or“life” of vehicle battery 36. In particular, range extender 16 generatesless electrical energy than is drawn from vehicle battery 36 on averageduring operation of the vehicle. In one embodiment, driver inputs 24,gear selector 26, and mode select input 82 are all provided at driverinterface 22.

In the illustrated embodiment, VCU 12 controls the operation of fanmotors 28 and 32 and water pump motors 30 and 34. Fan motors 28 and 32may be single phase or three phase motors. Fan motor 28 illustrativelydrives an engine fan 84 for cooling the engine of range extender 16 whenthe engine reaches high temperature levels. Fan motor 32 and water pumpmotor 30 illustratively drive a battery fan 88 and battery water pump86, respectively, for cooling vehicle battery 36 and related batterycircuitry of electrical system 10. Water pump motor 34 illustrativelydrives a water pump 90 for cooling the electrical components andcircuitry of electrical system 10, including rectifier 42, inverter 44,ECU 14, VCU 12, generator 17, converter 54, and vehicle motor 48. In oneembodiment, the electrical circuit of electrical system 10 is maintainedat a temperature of about 60 degrees or less. In the illustratedembodiment, water pump motor 34 is further used to preheat the oil ofthe engine of range extender 16.

Vehicle battery 36 is configured to provide power to vehicle motor 48for driving the electric vehicle. Vehicle battery 36 is illustratively a404V-280V DC battery, although other suitable voltage capacities forvehicle battery 36 may be used depending on vehicle requirements.Vehicle battery 36 is coupled to vehicle motor 48 via a voltagedistributor 46. Voltage distributor 46 is illustratively a high voltagedistribution box configured to route voltage received from vehiclebattery 36 and from range extender 16 to appropriate devices inelectrical system 10. In the illustrated embodiment, voltage distributor46 is coupled to vehicle battery 36 via wires 64, to rectifier 42 viawires 66, to inverter 44 via wires 80, to charger 52 via wires 68, andto DC/DC converter 54 via wires 70. Wires 64, 66, 68, 70, and 80illustratively include hot and ground wire pairs capable of transferringhigh voltage between the respective components.

Voltage distributor 46 routes the electrical power received from vehiclebattery 36 to DC/AC inverter 44. Inverter 44 converts the DC voltagefrom voltage distributor 46 to AC voltage and provides the AC voltage tovehicle motor 48 via motor cables 62. In the illustrated embodiment,vehicle motor 48 is a three-phase AC motor. In one embodiment, aregenerative braking system is utilized to generate electrical energyfrom the kinetic energy of the vehicle during vehicle braking. Inparticular, the kinetic energy of the vehicle is used to drive vehiclemotor 48 in the opposite direction, thereby causing vehicle motor 48 togenerate electrical energy that is fed back through voltage distributor46. The generated electrical energy may then be stored in vehiclebattery 36 or used to preheat a catalytic converter of range extender16, for example. Alternatively, a separate motor may be used for theregenerative braking.

Generator 17 provides electrical power to AC/DC rectifier 42 via cables60. In the illustrated embodiment, generator 17 is a three-phase motorthat is operated in reverse to function as an electricity generator. Inparticular, the engine of range extender 16 drives generator 17 andcauses generator 17 to produce AC power provided to rectifier 42.Rectifier 42 converts the AC voltage received from electrical generator17 to DC voltage. Voltage distributor 46 routes the generated DC voltagereceived from rectifier 42 to the appropriate destination in electricalsystem 10, such as to charge battery 36 or to drive vehicle motor 48directly. In one embodiment, generator 17 also serves as a starter forthe engine of range extender 16. In particular, vehicle battery 36 mayprovide a voltage to the motor of generator 17 via cables 60, causingthe motor of generator 17 to rotate in the forward direction to startthe engine of range extender 16. As such, an additional starter motorand alternator is not required, thereby reducing the size and weight ofrange extender 16.

Vehicle battery 36 illustratively includes a battery manager 38 thatmanages various parameters of vehicle battery 36. In one embodiment,battery manager 38 includes a computer with software that containslimits for the discharge rate, the charge rate, the maximum and minimumvoltage, and the maximum and minimum temperature of battery 36. Inparticular, battery manager 38 may monitor the level of charge invehicle battery 36 and initiate a control event detected by VCU 12 whenthe charge of vehicle battery 36 reaches a predetermined level. Forexample, when the stored charge of vehicle battery 36 reaches apredetermined low level, battery manager 38 may provide VCU 12 with a“low voltage” warning. In response, VCU 12 may instruct ECU 14 to startthe range extender 16 to generate more electrical energy that is fedback into electrical system 10 for charging vehicle battery 36.Similarly, when the stored charge of vehicle battery 36 reaches apredetermined high level, battery manager 38 may provide VCU 12 with a“high voltage” warning. In response, VCU 12 may instruct ECU 14 to stopor reduce the generation of electrical energy by generator 17. In theillustrated embodiment, battery manager 38 is configured to communicatewith various devices, including VCU 12, on communication network 40 toassist with the management of battery 36.

Charger 52 is configured to couple to an external power source forcharging battery 36. In one embodiment, charger 52 is a plug-in chargerthat connects to and draws electrical power from an electrical outlet tocharge battery 36. DC/DC converter 54 converts DC voltage from battery36 to a lower voltage level to provide a battery source 56. Batterysource 56, illustratively 12 volts, may be utilized by low-voltagedevices of the electric vehicle, such as lights and the instrumentpanel.

Referring to FIG. 2, exemplary control logic 100 is shown forcontrolling the operation of range extender 16. In the illustratedembodiment, control logic 100 is contained within a memory of VCU 12,although ECU 14 may alternatively contain at least a portion of controllogic 100.

Block 106 is true if a vehicle speed flag 102 is set or if a rangeextender ON flag 104 is set. In one embodiment, a button or switchlocated at driver interface 22 or instrument panel may be used to setrange extender ON flag 104 to initiate control logic 100 of FIG. 2. Inone embodiment, the selection of an operating mode of range extender 16with mode select input 82 (see FIG. 1) sets range extender ON flag 104.As such, a user may activate range extender 16 manually under certainconditions. Vehicle speed flag 102 is set when the electric vehicle isat or above a predetermined minimum vehicle speed. In the illustratedembodiment, the minimum vehicle speed required to set vehicle speed flag102 is about 55 kilometers/hour, although other suitable minimum vehiclespeeds may be selected. If the vehicle speed 102 drops below apredetermined minimum level, range extender 16 is switched OFFautomatically, as described herein. In the illustrated embodiment, rangeextender 16 is deactivated (i.e. block 106 goes from true to false) whenthe vehicle speed 102 drops below about 25 kilometers/hour, althoughother suitable minimum vehicle speeds may be selected. With rangeextender 16 only operating automatically at higher vehicle speeds, theroad noise or other noise from the electric vehicle serves to drown outthe noise generated by range extender 16.

The operating limits illustrated in block 110 are used to start or stoprange extender 16 automatically depending on several parameters ofvehicle battery 36. The limits illustrated in block 110 are exemplary,and other suitable limits may be provided at block 110 depending onvehicle configurations. In the illustrated embodiment, range extender 16is configured to be activated (i.e. block 110 is “true”) if the voltageof vehicle battery 36 drops to 280 volts or less, the charge percentageof vehicle battery 36 is less than 80% of full capacity, and thetemperature of vehicle battery 36 is less than about 41 degrees Celsius.At block 110, if the voltage of vehicle battery 36 rises to 390 volts,if the charge percentage of vehicle battery 36 meets or exceeds 80% offull capacity, or if the temperature of vehicle battery 36 meets orexceeds about 41 degrees Celsius, the control logic proceeds to block138. At block 138, action is taken by VCU 12 to respond to the exceedlimitations. Depending on the cause of the exceeded limits, VCU 12 maydeactivate generator 17 of range extender 16 and/or deactivate charger52 to reduce the likelihood of overloading vehicle battery 36.

Block 112 requires the selection of a mode of operation of the vehicle,such as the “sport” or “economic” modes described above. If blocks 106,110, and 112 are all true, the control logic proceeds to block 114. Inthe illustrated embodiment, range extender 16 is configured to generatea certain load (based on engine speed or rpm) depending on the vehiclespeed and the selected mode of operation of range extender 16. At blocks114 and 122, VCU 12 (or ECU 14) identifies the selected mode ofoperation for range extender 16. The mode of operation is illustrativelyselected with mode select input 82 of FIG. 1. In the illustratedembodiment, battery hold mode, battery charge mode, or range extendedmode may be identified at blocks 114 and 122. Once the mode of operationis identified, the run flag 130 is set at block 124.

Upon identifying the appropriate mode of operation for range extender 16and setting run flag 130, the control logic proceeds to block 126. Atblocks 126, 132, and 136, the selected mode of operation for rangeextender 16 is implemented by VCU 12 and/or ECU 14. As long as block 126is false, range extender 16 is run according to the selected mode ofoperation, as represented by block 136. As such, a startup event 140 isgenerated and range extender 16 is activated and run according to theselected mode of operation.

With the vehicle and range extender 16 running, the vehicle brake may beapplied which causes the regenerative braking to be initiated. In such acase, both range extender 16 and the regenerative braking systemgenerates electrical power that is fed back to vehicle battery 36. Inorder to avoid a current overload of vehicle battery 36, a flag 128 isset when the generated current supplied to vehicle battery 36 exceeds anupper threshold. For example, if the upper current threshold of vehiclebattery 36 is 80 amps, flag 128 is set when the combined currentgenerated by range extender 16 and the regenerative braking system meetsor exceeds 80 amps. In this situation, range extender 16 is deactivatedat block 134 by closing the throttle plate of the engine of rangeextender 16, thereby by stopping the generation of electrical power bygenerator 17. In one embodiment, if the upper current threshold limit isstill exceeded after stopping generator 17, the regenerative brakingsystem is disabled or the generated current from the regenerativebraking system is redirected in order to avoid overloading vehiclebattery 36. In one embodiment, flag 128 is set when the limitsillustrated in block 110 are exceeded. At block 134, a time delay may beimplemented before a startup event 140 may be generated and rangeextender 16 may be re-activated.

In one embodiment, the mode of operation may be changed on the flyduring the operation of the electric vehicle and range extender 16. Forexample, a user may select a new mode of operation with mode selectinput 82 (see FIG. 1) while range extender 16 is running in a differentmode of operation.

If block 106 is true, the control logic also proceeds to block 146. Asrepresented by blocks 142, 144, and 146, if the vehicle speed 102 is ator about zero and the vehicle is in a neutral gear, range extender 16may be run to charge vehicle battery 36. In particular, the user mustmanually select a button or other input device at the driver interfaceto set the range extender ON flag 104 and to activate range extender 16at block 148. The manual activation of range extender 16 at block 148may be used, for example, when the vehicle is stopped and vehiclebattery 36 is dropping to a low charge level, such as in a traffic jam.

In the illustrated embodiment, range extender 16 is configured togenerate a certain load depending on the vehicle speed and the selectedmode of operation of range extender 16. In each mode of operation, theengine speed of range extender 16 varies depending on vehicle speed.FIG. 3 illustrates the engine speed and the throttle opening of rangeextender 16 in an exemplary battery hold mode of operation for rangeextender 16. In the battery hold mode, the engine speed (RPM) of rangeextender 16 follows curve 116 and the throttle opening percentage ofrange extender 16 follows curve 118 in relation to the vehicle speed.The load generated by range extender 16 depends on the engine speed ofrange extender 16. In the exemplary battery hold mode of operation,range extender 16 generates a power curve 120 (see FIGS. 4 and 5) forthe illustrated vehicle speed range.

Power curve 182 of FIGS. 4 and 5 illustrates the exemplary averageelectrical power needed by vehicle motor 48 to drive the vehicle on asubstantially flat road or surface. As illustrated in FIG. 4, theelectrical power generated by range extender 16 in the battery hold modeis greater than or equal to the electrical power consumed on average byvehicle motor 48 when the vehicle is driving on a flat road for theillustrated range of speeds. As such, battery hold mode may be utilizedwhen the vehicle traverses both hilly and flat terrain. In the batteryhold mode illustrated in FIG. 4, range extender 16 creates supplementalelectrical energy between vehicle speeds of about 25 kilometers/hour and80 kilometers/hour.

Exemplary power curves for the battery charge mode and range extendedmode of operation are illustrated in FIG. 5. In a range extended mode,range extender 16 generates a power curve 184 for the illustratedvehicle speed range. As illustrated, the power generated by rangeextender 16 in the range extended mode is less than or equal to thepower consumed on average by vehicle motor 48 when the vehicle isdriving on a flat surface. In the illustrated embodiment, range extendedmode is configured to extend the range or “life” of vehicle battery 36and not necessarily maintain the charge of vehicle battery 36.

In a battery charge mode, range extender 16 generates a power curve 186for the illustrated vehicle speed range. As illustrated, the powergenerated by range extender 16 in the battery charge mode issubstantially more than the power consumed on average by vehicle motor48 when the vehicle is driving on a flat surface. As such, the batterycharge mode is used to charge vehicle battery 36 during operation of thevehicle.

For the battery hold and range extended modes of operation illustratedin FIG. 5, energy generation by range extender 16 is activated when thevehicle speed reaches about 55 kilometers/hour and is deactivated whenthe vehicle speed drops below about 25 kilometers/hour. In the batterycharge mode illustrated in FIG. 5, range extender 16 is configured togenerate electrical energy for all vehicle speeds, including vehiclespeeds between 0 and 55 kilometers/hour.

With reference now to FIG. 6, the vehicle has a cooling system showngenerally at 200 having a low temperature circuit 202 and a hightemperature circuit at 204. Low temperature circuit 202 is comprised ofan electrical water pump 206 and a radiator at 208 where water pump 206circulates low temperature cooling water through rectifier 42, inverter44, DC to DC converter 54, electrical drive motor 48 and generator 17.This cooling water also runs through an oil pre-heater located withinthe range extender engine as described herein.

A separate, and higher temperature circuit 204 is provided whichcirculates cooling water through the engine water jackets of the enginein a typical fashion. A second radiator 210 is provided for cooling theengine cooling water and a heating element 212 provides heating for thepassenger compartment. The vehicle can also have an onboard electricheater (not shown) and the system can determine whether it is moreefficient to run the range extender engine to provide the passengercompartment heating or to heat the engine by way of the electricalheater and recharge the batteries with the range extender.

As mentioned above, the system includes a range extender 16, which iscomprised of a generator 17 and, as shown in FIGS. 7-9, a 4-cycle engine290. The engine 290 is comprised of a crankcase housing 300, an oil panor sump 302, cylinder liner 304, head assembly 306 and valve cover 308.With reference now to FIG. 10, plural chambers are defined in the engineand by the plural sections 300, 302, 304 and 306 such as engine oil sump310, crank chamber 312, compression chamber 314 and cam shaft chamber316. With reference now to FIGS. 10, 11 and 12, oil sump 302 will bedescribed in greater detail.

As best shown in FIGS. 11A and 11B, oil sump 302 is defined by an upperbody portion 326 and a lower body portion 328 as described herein. Upperbody portion 326 is comprised of side walls 330, 332 and end walls 334,336. Oil sump 302 also includes a lower floor 340 having a pedestalportion 342 and an integral tubular portion 344 extending upwardlytherefrom. With reference now to FIG. 12, a filter assembly 350 is showninstalled within the oil sump 302 and includes a threaded bolt portion352, a tubular filter 354, and a transition section 356. As shown, ahole is drilled from wall 332 towards wall 330, and partially intopedestal 342 defining apertures 360 a and 360 b. The tubular portion 344is also drilled to define a hole 362 which intersects with hole 360 b.As should be appreciated, hole portion 360 a is threaded to receive boltportion 352. This allows filter assembly 350 to be positioned as shownin FIG. 12 with the transition portion 356 positioned in hole 360 b.

With reference now to FIGS. 11A, 11B, 12 and 13, the oil sump 302further includes a water fed heat exchanger shown generally at 370 inFIG. 12 and described herein. With reference first to FIGS. 11A and 11B,the upper portion 326 of oil sump 302 includes curved wall portions 372and 374 (FIG. 11A) defining corresponding concavities 376 and 378 (FIG.11B). As shown best in FIG. 13, water couplings 380 and 382 communicatewith concavities 376 and 378, respectively, and provide water in and outto the heat exchanger 370. With respect now to FIG. 11B, the lower sideof oil sump portion 326 includes a plurality of U-shaped fins such as390, 392 which surround a center wall 398. As shown in FIG. 11B, agasket 400 is positioned between portions 326, 328 and held together byway of fasteners 402. With respect again to FIG. 12, two separatechannels are defined, 410, 412, which communicate with respective watercouplings 382, 380, as further described herein.

With reference now to FIGS. 14-17, crank housing portion 300 will bedescribed in greater detail. As shown, crank housing 300 is shown as asplit housing defined by housing portions 300A and 300B. As shown,housing portion 300B has a plurality of threaded studs 440 threadedlyreceived in threaded apertures 442. Housing portion 300A includescorresponding apertures 444 positioned over the studs to complete thehousing assembly. As shown in FIG. 14, the lower housing portion 300 bdefines a crankshaft chamber 450 bound by a semi-circular wall 452 andend walls 454 and 456. Each of the end walls 454, 456 define bearingsurfaces 458, 460 as described herein.

The crank housing 300 also defines a plurality of mounting faces orflanges. For example, as shown in FIG. 14, a top face 470 is defined formating with the cylinder liner portion 304 as described herein. Agenerator mounting face is also defined by 472A and 472B, and has aplurality of mounting apertures at 474. As shown in FIG. 15, a lowermounting face 478 is provided for mounting with the oil sump 302. Withreference now to FIG. 16, the two housing halves 300A, 300B also definea mounting face 490A, 490B which receive a cover as further describedherein. Cam chain chamber 316, FIG. 16, is at least partially defined bythe wall 500 on housing portion 300B and the wall 502 on housing portion300A. Thus when the housing parts 300A and 300B are positioned together,the cam chain chamber 316 surrounds bearing surface 458 and is alsobounded by a rear wall defined by surfaces 510A on housing . portion300A and 510B on housing portion 300B. As shown in either of FIG. 14 or16, a cam chain channel 512 is provided which communicates through theupper surface 470 of crank housing 300 and also opens into cam chainchamber 316 as best shown in FIG. 17. As also shown in FIG. 16, housingportion 300B also includes a semi-cylindrical wall 514 extendingforwardly from surface 510B, having an access notch 516, as furtherdescribed herein.

As best shown in FIGS. 16 and 17, a channel is defined adjacent to crankchamber 450 defined by channel halves 520A (FIGS. 17) and 520B (FIG.16). A port is defined by portions 522A and 522B (FIG. 16) which in turncommunicates with the channel defined by 520A and 520B. It should beunderstood that the inner wall 524A (FIG. 17) and the inner wall 524B(FIG. 16) define a spaced apart slot therethrough such that the crankchamber 450 communicates with the channel defined by channel portions520A and 520B. Furthermore, the port defined by portions 522A and 522Bis the only communication between the crank channel 450 and the camchannel 316. Meanwhile the only communication between the cam shaftchamber 316 and the oil sump chamber 310 is through opening 530 (FIG.16) at the lowest point of this continuous wall 500. Finally, an oilinlet is defined by apertures 536 (FIGS. 17) and 538 (FIGS. 16 and 17).It should also be appreciated that aperture 536 is profiled tocorrespond with aperture 362 (FIG. 12).

With reference now to FIGS. 18 and 19, the crankshaft assembly is showngenerally at 540. The assembly 540 is comprised of a crankshaft 542,which has a split shaft having halves 542A and 542B connected togetherby way of pressed pin 544; and a connecting rod 546. The crankshaft 542also includes two output shaft ends, a first shaft end 550 having acoupling surface at 552 and a second shaft end 560 which is keyed to agear set 562 having a small diameter gear 564 and a large diameter gear566, as further described herein. As also shown, the end of shaft 560 isbored to provide an aperture at 570 which in turn communicates with bore572 through crankshaft portion 542B. As shown, pin 544 includes a boreat 574 which aligns with bore 572. Counterweights are provided at 576.

Finally, pin 544 includes end caps 578 defining an inner pin volume at580, and an access opening 582 positioned between the crankshaftportions 542 a, 542 b. As shown, connecting rod 546 is shown positionedbetween the crankshaft halves 542 a, 542 b and rotatably mounted to pin544 by way of a needle bearing at 590. As best shown in FIG. 19, theconnecting rod 544 has three indents 592 on each side of the connectingrod, as further described herein. Two roller bearings 594 and 596 arepositioned on opposite sides of pin 544 and rotatably mount thecrankshaft assembly 542 as further described herein. Lastly, a wiperseal 598 is provided adjacent to roller bearing 596 as further describedherein.

With reference now to FIG. 20, the head assembly 306 is shown having amain body portion 600. Assembly 306 includes double overhead cams 602,604 which are rotatably mounted in pairs of roller bearings 606 and 608(only one of each pair is viewed in FIG. 20). Cams 602 and 608 aredriven by respective gears 610, 612 and by timing chain 614. It shouldbe appreciated that timing chain 614 is trained around gear 564 (FIG.19), such that the crankshaft rotation drives the camshafts 602, 604. Asshown best in FIG. 21, housing 600 includes an upper wall 620 having thevalve ports 622 and a lower wall 630 having apertures 632 therethrough.An access channel is provided at 634, which is profiled to communicatewith channel 512 (FIGS. 16, 17) and to allow the chain 614 to passupwardly to the gears 610, 612.

With reference now to FIGS. 23 and 24, other aspects of the engine willbe described. As shown in FIG. 23, a reed valve 650 is positioned overand covers port 522. As shown in FIG. 24, chain guides 702, 704 areprovided for guiding the chain 614 and for maintaining the proper chaintension. With reference again to FIG. 23, a balancing gear 710 isprovided in meshed engagement with gear 566, which is driven by thecrankshaft 542. Gear 710 has a shaft 712 rotatably mounted as describedherein.

As shown in FIG. 23, a cover 740 is also shown having a flange 742 whichmates with flange surfaces 490A and 490B of crankcase assembly 300.Cover 740 further includes an oil distribution scraper 746, an oildistribution channel 748, and a roller bearing 744 which overlies shaft712 of balance gear 710. As shown, scraper 746 is attached to an insidesurface 750 of cover 740 and includes an elongate rail 752 and a shortrail 754. An extended tongue 756 projects beyond rail 752, 754 asfurther described herein.

Oil distribution channel 748 is comprised of a first seal 760 profiledfor receipt over crankshaft end 560, encompassing oil channel 570 (FIG.22). A second seal 762 is profiled to be positioned in aperture 538.Finally, an oil channel is defined within cover 740 at 766 as best shownin FIG. 10.

With reference now to FIG. 25, valve cover 308 is shown from anunderside view with oil distribution assembly 800 shown including adistribution member 802 for valve tappets/cams and rails 804, 806 forlubricating cam shaft 602 (FIG. 20). As shown in FIGS. 26 and 27,distribution member 802 comprises an upper tray 810 having a perimeterwall 812 extending around the tray and around a floor 814. A window 816extends through the floor 814 and is profiled for residing over camchain 614 as described herein. Mechanism 802 further includes a mountingboss 820 and openings 822 and 824 which communicate with the inner tray814.

With the above particulars of the engine described, the assembly of theengine will now be described. With reference first to FIGS. 11 b and 12,it should be understood that the oil pan 302 is assembled by placing thelower portion 328 and gasket against the lower surface of portion 326and providing fasteners to assemble the two components, 326, 328together. Oil filter assembly 350 is also installed as shown in FIG. 12.

As shown in any of FIGS. 14-17, studs 440 are threadably received inthreaded openings 442 whereupon the crankshaft assembly 540 (as shown inFIG. 18) is positioned within crankshaft chamber 450 (FIG. 14). Thispositions roller bearing 594 (FIG. 14) on surface 460 (FIG. 14) androller bearing 596 (FIG. 18) on surface 458 (FIG. 14). This alsopositions seal 598 within groove 462 (FIG. 14). It should be appreciatedthat this positions the gear set 562 (FIG. 18) overlying thesemi-cylindrical wall 514 as best shown in FIG. 23. It should also beappreciated that the cam chain 614 would be laced around drive gear 564prior to insertion in crankcase lower half 300 b.

With the crankshaft sub-assembly positioned as described above, theupper portion 300A of the crankcase assembly may now be slidablyreceived by positioning apertures 444 over each of the correspondingstuds 440 as best shown in FIG. 16. As shown in FIG. 17, upper crankcasehousing 300B is received over roller bearings 594, 596 with pins 640locating the bearings within receiving apertures 642 to prevent theouter race of bearings 594, 596 from spinning during the rotation of thecrankshaft. It should also be appreciated that during the assembly ofthe upper crankcase housing portion, the cam shaft drive chain 614 isfed upwardly through aperture 512 (FIG. 17) to pull the chain upwardlythrough the crankcase.

With respect now to FIG. 10, with a piston 636 attached to connectingrod 544, cylinder liner 304 may now be placed over piston 636 anddownwardly to be received on the top surface 470 (FIG. 16) of the uppercrankcase housing 300A. While not specifically described, it should beappreciated that cylinder liner 304 has apertures which match with studs440 such that cylinder liner stacks on top of crankcase housing 300 a,as best shown in FIG. 10.

With the head assembly 306 as shown in FIG. 20, head assembly 306 ispositioned over studs 440 with holes 632 (FIG. 21) received therein. Itshould be appreciated that studs 440 have a length appropriate to bereceived through apertures 632 with enough clearance to receivefastening assemblies such as washers and fastening nuts. The cam chain614 is then assembled around associated cam drive gears 610, 612 to theposition shown in FIG. 20. Valve cover 308 may then be attached overhead assembly 306 by way of fasteners.

With reference now to FIG. 28, the range extender assembly 16 is shownmounted within a vehicle forward of the drive motor 48. The rangeextender engine 290 is attached to generator 17 where generator 17 ismounted along, and facing forward relative to, longitudinal axis L.Drive motor 48 has output drive couplings 800 arranged along atransverse drive axis D. As shown, a frame bracket 802 is providedhaving mounting cylinders 804 which include rubber grommets to mount therange extender assembly 16 at three positions.

As mentioned above, the range extender 16 only operates for the purposeof charging the system batteries and therefore is not constantlyrunning. For that purpose, the oil is preheated by way of system waterflowing through couplings 380, 382. This flow of water is constantduring the operation of the vehicle in order to maintain the oil at aproper operating temperature. For that same reason, the catalyticconverter of the range extender is also preheated for a run readycondition.

The engine is designed such that oil pressure to the bearing points isnot necessary but rather a small flow of droplets are only required forproper lubrication. As mentioned above, all of the bearings are rollerbearings, particularly the main crank bearings 594, 596; and theconnecting rod bearing is a needle bearing 590 (FIG. 18). As alsomentioned, the overhead cam bearings 607, 608 (FIG. 20) are also rollerbearings. Thus a small amount of oil flow is adequate for the roller andneedle bearings lubrication.

As described, engine 290 does not even have a traditional oil pump butrather, the oil is siphoned under the natural operational movement ofthe piston. With reference to FIGS. 10, 18 and 19, the enginelubrication will be described. It should be appreciated that in FIG. 10,piston 636 is shown in the top dead center (TDC) position. During thepower stroke, piston 636 is forced downwardly and the reduction ofvolume in crank chamber 312 (together with the blow by gases around thepiston) pressurizes crankcase chamber 312. Recall that only one portcommunicates between the crankcase 312 and the cam chain drive chamber316, that is through port 522. Thus during the compression stroke, thegases in crankcase 312 exhausts through reed valve 650 (FIG. 23).

When the piston is at its lowest position, or bottom dead center (BDC),the piston begins to move upward, beginning the compression strokecompressing air and fuel within the compression chamber 314. The vacuumcreated within chamber 312 draws oil from the oil sump chamber 310through filter 354 into passageway 362, 536, 766 and into passageway 570within the crankshaft 542. This also draws oil into the internal volume580 within pin 544 through passageway 572. Oil reaches the needlebearings 590 through aperture 582. The continued rotation of crankshaft542 causes the centrifugal force on the oil to be released from theneedle bearing 590 through passage ways 592 (FIG. 19) into crank chamber312. In fact, once the engine is running, the centrifugal force of theoil together with the surface tension of the oil fluid, helps draw theoil through the aforementioned passages. It should also be appreciatedthat during the power stroke, the oil that is in the crank chamber 312is exhausted through the reed valve 650 into chamber 316.

With reference again to FIG. 23, the oil level is shown at its naturallevel within chamber 316, and aperture 516 allows oil to seek a levelwithin semi-circular wall 514. Rotation of the gears 566, 710 (FIG. 23)causes oil to be thrown onto rail 752 and to pool with the help of rail754 and traverse down rail 756. The oil is thereafter picked up by chain614 and carried through the crank housing 300, liner 304, and into thehead 306.

With reference now to FIGS. 30 and 31, the lubrication within the headassembly 306 will be described. As shown first in FIG. 30, chain 614throws oil into member 802 through window 816 and collects within member802. Oil then drips through aperture 822 (FIGS. 26-27) and throughopening 824 (FIG. 27) to lubricate lobes 605 on cam shaft 604. Therotation of the chain 614 together with the cam 602, 604, causes aspewing of the oil against rails 804, 806 (see FIG. 25) which causesdroplets of oil to lubricate the lobes 603 of cam 602 (FIG. 20). Also,due to the inclination of the engine (see FIG. 7) that is, with oildistribution member 802 on the high side, oil is also distributed tolobes 603 of cam 602 (FIG. 20). The general spray of oil within valvecover 308 lubricates bearings 606, 608. Oil is returned to the cam chainchamber 316 through the chain access openings 512 (FIGS. 16) and 634(FIG. 20) and back to oil sump chamber 310 by way of aperture 530, whichcontinues the lubrication cycle.

With reference now to FIG. 32, a sectional view of the range extenderwith coupled single-cylinder engine 290, the generator 17 located on theleft and the engine block of the combustion engine, here asingle-cylinder engine, on the right. The generator 17 is located in agenerator housing 900.

Of the combustion engine can be seen the crank shaft 542, the crank pin544, the connecting rod 546, the piston 636 as well as the cylinderliner 304 and of the electric drive can be seen the likewise hollowrotor shaft 902 of the generator with the generator/rotor 904.

As can be seen from FIG. 33, the crank shaft 542 and the rotor shaft 902are connected by a self-centering connection screw 906, whereby on thecrank shaft, a stub shaft 550 with spur gearing 552 and on the rotorshaft 902 a corresponding shaft 908 with spur gearing 910 are arranged,whereas this serration is self-centering, and is known as a“Hirth-Serration”. The two shafts are connected by a connecting screw912 and the two housings 900 and 304 are connected by screws 914 withoutcentering because the Hirth-Serration does the centering.

An advantageous consequence of such a connection is a substantialsimplification of the bearings of the two shafts, which enables simplelength adjustment of the shafts due to temperature changes. Thisconstruction only requires a fixed bearing 920 in the form of a ballbearing for the rotor shaft 902 and a first floating bearing 922 as ballbearing or roller bearing in the generator housing or inner ring as wellas third and fourth floating bearings 594 and 596 as roller bearingswithout axial in-runs in the engine housing, whereas the inner ring ispressed on the crank shaft or the crank shaft directly serves as runningsurface for the floating bearing without inner ring. The floatingbearings 594 and 596 can also be constructed as ball bearings with aslide fit in the housing or on the shaft.

From the above described arrangement of the coupling, numerousadvantages result, such as simple assembly by only one screw through thehollow shaft of the generator; simple preassembly of the two componentscombustion engine and generator; the connection is configured such thatthe pre-stress force of the screw is in every situation bigger than thetorque and bending moments generated by the combustion engine which workon the serration, thus achieving a very rigid connection and enablinguse of the high rotary mass of the generator as engine flywheel mass.

As the serration is self-centering, additional centerings on the housingare omitted. In this manner, an over-determinacy in the assembly can beavoided and the concentricity as well as the alignment of the twoaggregates is always achieved. In the axial direction, minor tolerancesare possible.

The shaft connections are made first and subsequently the housings arescrewed together. Due to the high precision of the Hirth-Serration inthe axial direction, it is possible to fix the whole connected shaftwith only one axial bearing, by which the known problems with respect tolinear expansion due to temperature influence can be eliminated.

As the generator is very sensitive to the play both in radial and axialdirections because of the efficiency of the windings and the permanentmagnets, and as the efficiency drastically deteriorates with large play,it would be ideal if the generator could be aligned exactly and all ofthe linear expansion on the combustion engine could be absorbed andbalanced in spite of the rigid connection. The axial alignment on thegenerator is important because the rotation speed and positionmeasurement of the generator is read by a decoder/rotary encoder mountedon the end side. This decoder is not able to overcome long axialdistances because of its design. The axial alignment of the generatorhousing and the generator shaft is thus preferably to be made on theside of the decoder.

For this reason, the combustion engine can be configured such that itcan absorb all of the length extension of the connected shaft in thecrankshaft drive. Crank shaft and connection rod have enough play inaxial direction to absorb the extension. The axial bearing on the enginecan be omitted. The crank shaft and the connection rod merely have anin-run for limitation in axial direction, which is only used in thepre-assembly state of the engine without the generator.

As soon as the engine and the generator are connected, the generatortakes over the axial alignment. The bearings on the engine may befabricated with ball bearings as floating bearings as set out in FIG. 35or alternatively with roller bearings or spherical roller bearings. Theconnection rod has enough play on the piston pin to absorb the axialextension. Below, the connection rod passes between the crank webs. Thisleads to a compact combination of the aggregates, whereby the generatorwith its large rotary mass is used as flywheel on the combustion engine,thus resulting in a substantial weight saving and an optimization ofinstallation space.

With reference now to FIG. 36, an engine dampening system 950 for engine290 and generator 17 is shown. Engine 290 includes an air intake system952 comprised of an air filter 954 coupled to throttle body 956 and toair manifold 958 by way of hoses 960, 962. As shown, air filter 954 isattached to frame 964 by way of a coupling mechanism shown generally at966. Coupling mechanism 966 could be a direct connection onto the frameor could be a bracket of known construction. Without dampening system950, engine 290 may vibrate causing vibration transfer to the air filter954 and to frame 964 which may be felt by the driver and/or passengers.This vibration is enhanced by the remote location of the throttle body956 which is coupled directly to engine 290.

As shown vibration dampening system 950 is comprised of a plurality ofsupport arms 970 rigidly connected to engine 290 and also coupled to adampening weight 972. Dampening weight 972 may be connected only engine290 as shown in FIG. 36, or may be directly and rigidly coupled tothrottle body 956 by way of coupling 974, as shown in FIG. 37.

A further alternative as shown in FIG. 38, allows dampening weight 972to be movable relative to throttle body 956 by way of coil springs 976,978. In this example, rod 974′ passes through mass 972, with springs onopposite sides of mass 972. For a single cylinder engine as shownherein, it has been found that a mass of approximately 6 KG isappropriate.

Thus as shown, vibration from engine 290 is transferred to dampeningweight 972. In the embodiment of FIG. 36, the engine vibration alone isdampened, and in the embodiment of FIGS. 37 and 38, throttle body 956,due to its direct coupling to dampening weight 972 through coupler 974is also dampened, and vibrates at the same frequency as weight 972 andengine 290. In all embodiments, less vibration is inherently transferredto frame 964.

1. A vehicle, comprising: an electric propulsion drive assembly; a firstcooling circuit for the electric propulsion drive assembly; an engine,including a crankcase having an oil sump; and a pre-heater for the oilsump in fluid communication with the first cooling circuit forpre-heating engine oil.
 2. The vehicle of claim 1, further comprising asecond cooling circuit for the engine.
 3. The vehicle of claim 2,wherein the first and second cooling circuits are discrete.
 4. Thevehicle of claim 2, wherein the first cooling circuit has a lowermaximum operating temperature than the second cooling circuit.
 5. Thevehicle of claim 1, wherein the pre-heater is integrated with the oilsump of the crankcase.
 6. The vehicle of claim 1, wherein the oil sumphas a lower surface defining a portion of the pre-heater.
 7. The vehicleof claim 6, wherein the oil sump lower surface defines coolingpassageways and the pre-heater further comprises a cover plate enclosingthe passageways.
 8. The vehicle of claim 2, wherein the second coolingcircuit includes a passenger compartment heater.
 9. The vehicle of claim1, further comprising an electric storage unit, and a generator coupledto the engine for recharging the electric storage unit.
 10. The vehicleof claim 1, wherein the engine and generator define a range extender.11. The vehicle of claim 1, further comprising a control mechanism tostart the engine and generator at defined charge levels of the electricstorage unit.
 12. The vehicle of claim 1, further comprising an electricheater for the passenger compartment and a control circuit to determinewhether to operate the electric heater, or to start the engine andoperate the passenger compartment heater of the second cooling circuit.13. An engine, comprising: an engine, including a crankcase having anoil sump; and a pre-heater for pre-heating engine oil in the oil sump,the pre-heater being integrated with the oil sump of the crankcase. 14.The vehicle of claim 13, wherein the oil sump has a lower surfacedefining a portion of the pre-heater.
 15. The vehicle of claim 14,wherein the oil sump lower surface defines cooling passageways and thepre-heater further comprises a cover plate enclosing the passageways.